This book constitutes the refereed proceedings of the IFIP-TC6 4th International Working Conference on Active Networks, IWAN 2002, held in Zurich, Switzerland, in December 2002.The 20 revised full papers presented were carefully reviewed and selected from 53 submissions. Among the topics addressed are router architectures, reconfigurable systems, NodeOS, service deployment, active network services, active network queries, network management agents, active network performance, mobile communications, programmable networks, network execution environments, active network architecture, group communication, peer-to-peer networks, and interaction detection.

Snow on Silk: A NodeOS in the Linux Kernel.- PromethOS: A Dynamically Extensible Router Architecture Supporting Explicit Routing.- The OKE Corral: Code Organisation and Reconfiguration at Runtime Using Active Linking.- Lightweight Thread Tunnelling in Network Applications.- RADAR: Ring-Based Adaptive Discovery of Active Neighbour Routers.- Integrated Service Deployment for Active Networks.- Component-Based Deployment and Management of Services in Active Networks.- ANQL - An Active Networks Query Language.- Predictable, Lightweight Management Agents.- Open Packet Monitoring on FLAME: Safety, Performance, and Applications.- Active Networks for 4G Mobile Communication: Motivation, Architecture, and Application Scenarios.- Evolution in Action: Using Active Networking to Evolve Network Support for Mobility.- AMnet 2.0: An Improved Architecture for Programmable Networks.- Design and Implementation of a Python-Based Active Network Platform for Network Management and Control.- Designing Service-Specific Execution Environments.- ROSA: Realistic Open Security Architecture for Active Networks.- A Flexible Concast-Based Grouping Service.- Programmable Resource Discovery Using Peer-to-Peer Networks.- Feature Interaction Detection in Active Networks.- Flexible, Dynamic, and Scalable Service Composition for Active Routers.